This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A031308 #6 Mar 01 2023 13:18:43 %S A031308 9,28,48,68,88,108,128,148,168,171,173,175,177,179,181,183,185,187, %T A031308 188,189,217,247,277,307,337,367,397,427,457,461,464,467,470,473,476, %U A031308 479,482,485,487,488,517,547,577,607,637,667,697 %N A031308 Position of n-th 9 in A031298. %Y A031308 Cf. A031298. %K A031308 nonn %O A031308 1,1 %A A031308 _Clark Kimberling_